Fully-Explicit and Self-Consistent Algebraic Reynolds Stress Models
Fully-Explicit and Self-Consistent Algebraic Reynolds Stress Models

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-07-03

Total Pages: 32

ISBN-13: 9781722250218

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A fully-explicit, self-consistent algebraic expression for the Reynolds stress, which is the exact solution to the Reynolds stress transport equation in the 'weak equilibrium' limit for two-dimensional mean flows for all linear and some quasi-linear pressure-strain models, is derived. Current explicit algebraic Reynolds stress models derived by employing the 'weak equilibrium' assumption treat the production-to-dissipation (P/epsilon) ratio implicitly, resulting in an effective viscosity that can be singular away from the equilibrium limit. In the present paper, the set of simultaneous algebraic Reynolds stress equations are solved in the full non-linear form and the eddy viscosity is found to be non-singular. Preliminary tests indicate that the model performs adequately, even for three dimensional mean flow cases. Due to the explicit and non-singular nature of the effective viscosity, this model should mitigate many of the difficulties encountered in computing complex turbulent flows with the algebraic Reynolds stress models. Girimaji, Sharath S. Langley Research Center NAS1-19480; RTOP 505-90-52-01...

Engineering Turbulence Modelling and Experiments - 3
Engineering Turbulence Modelling and Experiments - 3

Author: G. Bergeles

Publisher: Newnes

Published: 2012-12-02

Total Pages: 932

ISBN-13: 0444600132

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This book presents and discussses new developments in the area of turbulence modelling and measurements, with particular emphasis on engineering-related problems. At present, turbulence is one of the key issues in tackling engineering flow problems. Powerful computers and numerical methods are now available for solving the flow equations, but the simulation of turbulence effects which are nearly always important in practice, is still in an unsatisfactory state and introduces considerable uncertainities in the accuracy of CFD calculations. These and other aspects of turbulence modelling and measurements are dealt with in detail by experts in the field. The resulting book is an up-to-date review of the most recent research in this exciting area.

Modeling Complex Turbulent Flows
Modeling Complex Turbulent Flows

Author: Manuel D. Salas

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 385

ISBN-13: 9401147248

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Turbulence modeling both addresses a fundamental problem in physics, 'the last great unsolved problem of classical physics,' and has far-reaching importance in the solution of difficult practical problems from aeronautical engineering to dynamic meteorology. However, the growth of supercom puter facilities has recently caused an apparent shift in the focus of tur bulence research from modeling to direct numerical simulation (DNS) and large eddy simulation (LES). This shift in emphasis comes at a time when claims are being made in the world around us that scientific analysis itself will shortly be transformed or replaced by a more powerful 'paradigm' based on massive computations and sophisticated visualization. Although this viewpoint has not lacked ar ticulate and influential advocates, these claims can at best only be judged premature. After all, as one computational researcher lamented, 'the com puter only does what I tell it to do, and not what I want it to do. ' In turbulence research, the initial speculation that computational meth ods would replace not only model-based computations but even experimen tal measurements, have not come close to fulfillment. It is becoming clear that computational methods and model development are equal partners in turbulence research: DNS and LES remain valuable tools for suggesting and validating models, while turbulence models continue to be the preferred tool for practical computations. We believed that a symposium which would reaffirm the practical and scientific importance of turbulence modeling was both necessary and timely.

Engineering Turbulence Modelling and Experiments 6
Engineering Turbulence Modelling and Experiments 6

Author: Wolfgang Rodi

Publisher: Elsevier

Published: 2005-05-05

Total Pages: 1011

ISBN-13: 0080530958

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Proceedings of the world renowned ERCOFTAC (International Symposium on Engineering Turbulence Modelling and Measurements).The proceedings include papers dealing with the following areas of turbulence:·Eddy-viscosity and second-order RANS models ·Direct and large-eddy simulations and deductions for conventional modelling ·Measurement and visualization techniques, experimental studies ·Turbulence control ·Transition and effects of curvature, rotation and buoyancy on turbulence ·Aero-acoustics ·Heat and mass transfer and chemically reacting flows ·Compressible flows, shock phenomena ·Two-phase flows ·Applications in aerospace engineering, turbomachinery and reciprocating engines, industrial aerodynamics and wind engineering, and selected chemical engineering problems Turbulence remains one of the key issues in tackling engineering flow problems. These problems are solved more and more by CFD analysis, the reliability of which depends strongly on the performance of the turbulence models employed. Successful simulation of turbulence requires the understanding of the complex physical phenomena involved and suitable models for describing the turbulent momentum, heat and mass transfer. For the understanding of turbulence phenomena, experiments are indispensable, but they are equally important for providing data for the development and testing of turbulence models and hence for CFD software validation. As in other fields of Science, in the rapidly developing discipline of turbulence, swift progress can be achieved only by keeping up to date with recent advances all over the world and by exchanging ideas with colleagues active in related fields.

Turbulent Flow
Turbulent Flow

Author: Peter S. Bernard

Publisher: John Wiley & Sons

Published: 2002-11-14

Total Pages: 512

ISBN-13: 0471275387

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Provides unique coverage of the prediction and experimentationnecessary for making predictions. Covers computational fluid dynamics and its relationship todirect numerical simulation used throughout the industry. Covers vortex methods developed to calculate and evaluateturbulent flows. Includes chapters on the state-of-the-art applications ofresearch such as control of turbulence.

Transition, Turbulence and Combustion Modelling
Transition, Turbulence and Combustion Modelling

Author: A. Hanifi

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 540

ISBN-13: 9401145156

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This single-volume work gives an introduction to the fields of transition, turbulence, and combustion modeling of compressible flows and provides the physical background for today’s modeling approaches in these fields. It presents basic equations and discusses fundamental aspects of hydrodynamical instability.

Theories of Turbulence
Theories of Turbulence

Author: Martin Oberlack

Publisher: Springer

Published: 2014-05-04

Total Pages: 377

ISBN-13: 3709125642

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The term "turbulence” is used for a large variety of dynamical phenomena of fluids in motion whenever the details of the flow appear to be random and average properties are of primary interest. Just as wide ranging are the theoretical methods that have been applied towards a better understanding of fluid turbulence. In this book a number of these methods are described and applied to a broad range of problems from the transition to turbulence to asymptotic turbulence when the inertial part of the spectrum is fully developed. Statistical as well as nonstatistical treatments are presented, but a complete coverage of the subject is not attempted. The book will be of interest to scientists and engineers who wish to familiarize themselves with modern developments in theories of turbulence. The fact that the properties of turbulent fluid flow are addressed from very different points of view makes this volume rather unique among presently available books on turbulence.

Turbulent Flows
Turbulent Flows

Author: Stephen B. Pope

Publisher: Cambridge University Press

Published: 2000-08-10

Total Pages: 810

ISBN-13: 9780521598866

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This is a graduate text on turbulent flows, an important topic in fluid dynamics. It is up-to-date, comprehensive, designed for teaching, and is based on a course taught by the author at Cornell University for a number of years. The book consists of two parts followed by a number of appendices. Part I provides a general introduction to turbulent flows, how they behave, how they can be described quantitatively, and the fundamental physical processes involved. Part II is concerned with different approaches for modelling or simulating turbulent flows. The necessary mathematical techniques are presented in the appendices. This book is primarily intended as a graduate level text in turbulent flows for engineering students, but it may also be valuable to students in applied mathematics, physics, oceanography and atmospheric sciences, as well as researchers and practising engineers.

Fluid Mechanics and the SPH Method
Fluid Mechanics and the SPH Method

Author: Damien Violeau

Publisher: Oxford University Press

Published: 2012-05-03

Total Pages: 611

ISBN-13: 0199655529

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This book presents the SPH method for fluid modelling from a theoretical and applied viewpoint. It explains the foundations of the method, from physical principles, and will help researchers, students, and engineers to understand how the method should be used and why it works well.